import sys


file1=open(sys.argv[1],'r')
file2=open(sys.argv[2],'w')
for line in file1:
    line_list=line.strip().split('\t')
    if len(line_list[0])==2:
        line_list[0]='Chr'+line_list[0]
        for i in line_list:
            file2.write(i+'\t')
        file2.write('\n')